RE: Pre-Historic Nookie!
August 23, 2018 at 6:17 pm
(This post was last modified: August 23, 2018 at 6:25 pm by Anomalocaris.)
(August 23, 2018 at 5:54 pm)Khemikal Wrote: I give you the poodle..and the great dane. Both in the same species, as a wolf.
I feel like there's a disconnect here. I'm only relating why we ended up classifying neanderthalis as a subspecies of homo sapiens, like ourselves.
-and, yes, categorically, three populations that have not yet completed any speciation event from their parent population are subspecies. That's what a subspecies -is-. If they did complete one, they would no longer be a subspecies, they would become their own species.
They can each be their own species and still occasionally fruitfully interbreed. That’s the point. Some evidence of interbreeding is not conclusive evidence that they were of the same specie.
Many species today carry evidence of minor genetic contributions likely from other populations that are closely related but not considered its own specie. It is by no means rare or odd. The species are considered separate because they seldom or are never actually observed to interbreed and are substantially different.
Poodle and Great Dane can interbreed (sometimes with human help) and produce similar sex ratio and rate of fertility amongst the offsprings as if each breaded with another like itself. That’s why they are considered to be of the same specie. There is no strong evidence of that being the case between Neanderthals, Denisovans and HSS. There seems to be some evidence genetic contribution from Neanderthals only came from one sex. This suggest only one type of pairing (for example the female has to be Neanderthal) between HSS and Neanderthals can produce offsprings, or only offsprings of a specific sex is fertile, or there was only ever extremely few, perhaps just one, successful pairing and all of our Neanderthal genes came from that one instance and is indelibly marked by the specific circumstance of that one occurrence.
All these, if verified, would suggest Neanderthals and HSS are considerably further apart, than sub-species, with greater barrier to successful interbreeding than would normally be found in populations lumped together as variations of the same specie.
The fact that Neanderthal genes are ubiquitous amongst HSS is no proof of frequent genetic infusion. It is rather evidence that those who carry these genes enjoy significant evolutionary advantage.
